Plastron respiration by aquatic insects

A submerged water boatman (Notonecta) hangs inverted from the water surface. Bubbles along the insect's thorax and head facilitate oxygen and carbon dioxide exchange with the water column and allow the insect to remain underwater for extended periods. (Photo credit: J.W.M. Bush).


Scanning electron microscope images of the integument of the water-walking insect Mesovelia. The rough, waxy hairs support a plastron air bubble, which allows the insect to breathe while submerged underwater. Respiration occurs through spiracles, an example of which is shown in (d). (Photo credit: M. Prakash).


The rough, waxy exterior surface of many insects and spiders confers water-repellent properties that allow arthropods to walk on water, survive accidental collision with rain drops and even breathe while submerged. In the latter case, respiration occurs via a "plastron" air bubble, across whose surface there is an exchange of oxygen and carbon dioxide. Working with John W.M. Bush (MIT), I have, by way of theoretical modeling, examined circumstances in which the respiratory function of the plastron is particularly advanced, such that arthropods may remain below the water surface indefinitely. As indicated by the following reprint, this analysis combines biology, surface and gas-phase chemistry as well as interfacial mechanics and may have important biomimetic applications.

Publication:
  • Breathing underwater: the mechanics of plastron respiration (J. Fluid Mech. 608, with J.W.M. Bush) (link)

    Related publications and presentation:
  • Vector field model for insect microstructure arrays (.pdf)
  • A Mathematical model to capture complex microstructure orientation on insect wings (PLoS One 7, with D.T. Polet and F.A.H. Sperling) (link)
  • Plastron induced drag reduction and increased slip on a superhydrophic sphere (Soft Matter 7, with G. McHale and M.I. Newton) (link)
  • Formation and stability of oxygen-rich bubbles that shape photosynthetic mats (Geobiology 8, with T. Bosak, J.W.M. Bush and others) (link)